Therefore, the main television antenna generally comprises a retractable rigid or telescopic element housed inside the telephone casing and which must be extracted from it and “unfolded” to extend to a length approximately equal to a quarter of the wavelength signals in order to allow signal reception.
With such an arrangement the quality of the radiotelevision signal reception strongly relies on the ability of the user to correctly unfold and orientate the main television antenna.
Moreover, when this antenna is unfolded it increases the bulkiness of the mobile telephone and the design of the latter may become unaesthetic.
To improve the situation it has been proposed to use a main television antenna built-in inside the telephone casing. More precisely, to allow a signal reception in the mobile television band it has been proposed to use a Planar Inverted F Antenna (PIFA) mounted on the printed circuit board (PCB) of the mobile telephone. Such an arrangement is notably described in patent document US 2001/0050643.
This antenna allows effectively to receive signals in the mobile television band, but its bandwidth is normally too narrow to allow a signal reception over the television band (for the antenna heights allowable in mobile phones). Moreover, since this antenna is not adapted to reject the radiotelephone signals, interference may occur between television and radiotelephone signals, which may induce a quality degradation of the displayed television pictures.